Answer:
The amount of salt are 159.56 pounds.
Step-by-step explanation:
The volume of soil in top 6 inches in an area of 1 acre is calculated as

Since it is given that 1 cubic meter of the soil has a weight of 1100 kg thus 616.74 cubic meters of soil shall have a mass of 616.74 x 1100 = 678414 kg
Since it is given that 1 kg of the soil shall have 100 milligrams of the salt thus 678414 kg shall have 678414 x 100 milligrams of salt
Thus the amount of salt in the given volume of soil shall be 67.8414 kilograms.
Thus the mass in pounds shall be 2.205 x 67.8414 kg =149.56 pounds